One way stock 1.0 heat shielding is a bit unfair versus old DRE mod's heat sheilding.

[smjjames]

I am attempting to reentry this craft by letting the atmosphere slowly bring down my speed.

Incredibly slow way, yes, but I'm trying to figure out the reentry mechanics.

Also, last time I reentered, the pod exploded from overheating.

[DJK]

What picture?

Sorry about the screw-up, post is fixed, let me know if you can view the image

https://www.dropbox.com/s/ayomiv2uaxq3wj3/reentry.png?dl=0

[Dunbaratu]

ola: as the thread has been pointing out, capsules are stable. It's when you add very large very light things on their bottom, they become unstable.

Even when that very large very light thing is a heat shield? That defeats the entire point of having a heat shield when adding just a heat shield alone (even without the science jr module) causes you to flip over nose first. Read the thread.

[Stormweaver]

I can confirm - with just a Mk-1 capsule, a parachute and heatshield, the craft is stable around 30 degrees off the retrograde marker. Doesn't really matter what direction it's offset, but it won't stay retrograde without reaction wheels.

Oh, and it's enough to overheat the capsule at that angle. Might just be me playing at 120% for that one though.

[MrCynical]

There does seem to be a slight snag with the system at present in that the best way to reenter the capsule without it flipping over is to deploy the parachute at 2000+ m/s and blazing hot. That keeps it the right way up no problem. And it doesn't rip off, catch fire or laminate the kerbal on the cabin wall from the ridiculous g-forces either.

With DRE the heat shield was always a very heavy component which seemed to handle this rather better.

[Eric S]

I've had no problems with reentering the mk1 capsule. Mk16 parachute on top, two or three goo canisters, no heat shield, initial periapsis of about 30km, SAS turned off. Capsule starts to correctly orient itself at around 50km altitude, and by the time reentry heat starts is glued to the retrograde marker on the navball.

I'll probably need a heat shield if I do a direct landing from a Mun/Minmus return since the capsule heat is hitting just over 2K and it has a 2.4K heat limit.

This was with a fresh install, both unmodded and with KER installed.

[The Czosnex]

Welp, in real life first missions like Mercury and Gemini didn't have giant science bays and containers sticking out. The capsules were compact and not tall. If only the materials bay was smaller jsut like the goo bay that got downsized in 1.0, it would help a bit.

[tater]

Deploying a chute for reentry is "not a thing." It is 100% counterintuitive. Attempts to use SAS (with skilled crew) to keep the craft pointed properly… don't work, it starts shaking like crazy as the new "SAS=skill" stuff and the new atm model don't seem to like each other.

Did no one try to renter a "mercury" capsule in testing?

Also counterintuitive is to NOT put a heat shield on a mk1, I assumed that "stock" was unlike DRE in this regard? Is the mk1 supposed to not use a heat shield part? I would find that a bad choice for stock unless there is a huge warning not to apply a heat shield part to that pod as new players will likely assume this is required. I can test later.

Edited April 27, 2015 by tater

[NathanKell]

Have confirmed heat shields are screwy.

tater: a mk1 pod + chute, never seen it stabilize in that orientation for me. Heatshields are screwy though.

[Vorg]

I can see and agree with little things like temp sensors being massless. I question making the small batteries massless. But heat shields? That must be a bug

[smjjames]

Deploying a chute for reentry is "not a thing." It is 100% counterintuitive. Attempts to use SAS (with skilled crew) to keep the craft pointed properly… don't work, it starts shaking like crazy as the new "SAS=skill" stuff and the new atm model don't seem to like each other.

Did no one try to renter a "mercury" capsule in testing?

Also counterintuitive is to NOT put a heat shield on a mk1, I assumed that "stock" was unlike DRE in this regard? Is the mk1 supposed to not use a heat shield part? I would find that a bad choice for stock unless there is a huge warning not to apply a heat shield part to that pod as new players will likely assume this is required. I can test later.

As far as I know, no.

Also, how is it counterintuitive to not put a shield on a Mk1? Mine exploded in reentry.....

[JWag]

If heatshields are massless and have drag, would that explain the wonky orientation?

[smjjames]

I can see and agree with little things like temp sensors being massless. I question making the small batteries massless. But heat shields? That must be a bug

Yeah, shouldn't those things like, wiegh a ton?

[WOODY01]

well after a bit of career ii found the answer- just upgrade your Astronaut complex ASAP and get EVAs anything beyond Goo and little experiments should be jettisoned before hitting atmo and collecting science with EVAs

This is what I ended up doing. I tried bring a Scince Jr back and I just kept flipping nose down and no amount of corrections would fix it. The closest I got was being sideways.

I tried adding extra weight by adding an addittional Goo Bays in the service comparptment, then an additional heatshield, the small Lander legs none alone or together added enough weight to keep the nose up and the heatshield orientated correctly.

I thought about adding fins on the capsule to keep it orientated correctly but it just looks bad.

A capsule by itself does fine, once everthing blowsup it orientates nicely.

[Jovus]

ola: as the thread has been pointing out, capsules are stable. It's when you add very large very light things on their bottom, they become unstable.

This has not been my experience with a plain Mk 1-2 capsule + 2.5m heat shield with 2.5m chute on top and no other parts while coming down from a 79km x 72km LKO. I will do some more testing and confirm, however.

[smjjames]

Also, has anybody tried to do reentry with the heatshield on top like I did? Which was an attempt to work around the problem described.

[ola]

Yeah, shouldn't those things like, wiegh a ton?

The heat shield on the Gemini weighed 144 kg.

[Dunbaratu]

They appear to have mass in the VAB. When adding them to a vessel they do make the engineer readout increase the mass. Not sure why they behave so screwy in practice though.

[smjjames]

I'm a bit surprised that they missed this bug actually, did they not test with mercury/gemini/apollo reentries?

[FlipNascar]

Also, has anybody tried to do reentry with the heatshield on top like I did? Which was an attempt to work around the problem described.

I did it like this just now to ensure Valentina didn't get creamed coming home from her first Munar orbit. Got flipped around at some point between 39km and the 29km from this screenshot. For launch I put a decoupler atop the heatshield, and a nose cone.

[Brotoro]

Yeah, shouldn't those things like, wiegh a ton?

Heat shields? The Mercury capsule heat shield (1.9 meters in diameter) had a mass of 272 kg. I'm sure we have lighter, better heat shields nowadays.

So, no...not a ton.

[Dunbaratu]

I'm a bit surprised that they missed this bug actually, did they not test with mercury/gemini/apollo reentries?

That's what's so weird. I mean this is like one of the very first things anyone tries to do in a career game once they get their first ability to make an orbit.

[Holyvision]

So we know that something is haywire with the new heat shields, understood.

But these crazy parachutes... Can this can be confirmed to be working as intended or not? Surviving a 3000m/s re-entry when deployed/armed in atmosphere, without burning up, ripping off, or flattening Kerbols? What new magic material did they discover on Kerbin??!?

[ola]

Heat shields? The Mercury capsule heat shield (1.9 meters in diameter) had a mass of 272 kg. I'm sure we have lighter, better heat shields nowadays.

So, no...not a ton.

It was made out of beryllium though, the Gemini heat shield was much lighter at 144 Kg and the first U.S. capsule which used glass fibre/phenolic resin. Still, both shields were heavier than the massless ones in KSP stock.

[smjjames]

Heat shields? The Mercury capsule heat shield (1.9 meters in diameter) had a mass of 272 kg. I'm sure we have lighter, better heat shields nowadays.

So, no...not a ton.

Okay. I just imagined that they were thick and heavy or something. A ton would probably have been a massive exaggeration anyway.

- - - Updated - - -

Also, I don't know if a mod did it or a dev did it, but someone made that massless heat shield bug report thread as [not a bug/intended], so, I dunno, misunderstanding somewhere?

As for the chutes not ripping apart, they did that in 0.90, they won't rip apart even if you reenter at 14k m/s.